1. Field of the Invention
This invention relates to a driving power transmitting mechanism of a vehicle.
2. Description of Related Art
A conventionally rear wheel drive system of a vehicle is disclosed in Japanese Patent Public Disclosure No. 62-94,421, laid open to the public in 1987. This rear wheel drive system includes a pinion shaft meshed with a crown gear of a rear drive shaft within a speed reduction mechanism so that the rotation of the pinion shaft is transmitted to the rear drive shaft. Left and right ends of the rear drive shaft are connected with left and right rear axles through left and right hydraulic clutches, respectively, so that the left and right rear axles can be driven independently by controlling the enagement and disengagement of the left and right clutches.
It should, however, be noted that the conventional rear drive system is disadvantageous in that the left and right hydraulic clutches disposed at opposite sides of the speed reduction mechanism results in a spaced rear wheel drive system.
Moreover, the conventional system necessitates a space for arranging an oil pump for supplying hydraulic pressure for the hydraulic clutches. This is because the oil pump is separate from the rear wheel drive system.
In addition, since the oil pump is disposed away from the hydraulic clutches, the oil passage connecting therebetween long to cause undesirable pressure drop of the operating hyraulic pressure for the clutches. This may affect the reliability of operation of the hydraulic clutches.